Party rule, for short

• "We're not serving liquor," briefly
• BBQ invite letters
• Party invite letters
• "I'm not providing, you drunks!"
• Abbr. in many a party invitation
• Invitation abbreviation
• Informal invitation letters
• Low-budget party letters
• Party directive, briefly

Wikipedia Word definitions in Wikipedia
BYOB is an initialism used on party invitations, meaning "bring your own beverage" or variants. BYOB may also refer to: BYOB (musician) , an English musician B.Y.O.B. (song) , a song by System of a Down from their album Mezmerize BYOB (programming language) ...